While adding an xfstest for the missing file extent problem I fixed with the series btrfs: fix hole corruption issue with !NO_HOLES I was failing to fail my test without my patches, despite the file system being actually wrong. It turns out because the normal check mode sets its expected start to the first file extent it finds, instead of 0. This means it misses any gaps between 0 and the first file extent item in the inode. The lowmem check does not have this issue, instead it doesn't take into account the isize of the inode, so improperly fails when we have a gap but that is outside of the isize. I fixed this as well. With these patches we're able to properly find another set of corruptions, and now my xfstest acts sanely. Thanks, Josef
